In many large-scale manufacturing contexts, assembly precision is a fundamental requirement to maintain the engineering design intent, and for certification, by a customer or a government agency, that the manufactured product is fit for its intended use. Currently, large-scale manufactured items, and subassemblies for such items, are designed using computer-aided design (CAD) and/or computer-aided manufacturing (CAM) software. This software typically allows for product design modeling in three-dimensional (3D). The 3D design is then converted to standard orthogonal two-dimensional drawings (2D), which is, from then on, considered the official “authority for manufacturing”.
From the 2D engineering drawings, monolithic Floor Assembly Jigs and applied tooling fixtures, e.g. drill & locating jigs, are designed and built. The detail parts and subassemblies configuration is maintained and the tool becomes the control media to insure engineering configuration is achieved. Because the jigs and tools are often fixed, and the parts must be assembled while attached to the tool, adherence to the engineering design standards, within a specific tolerance, is maintained.
However, this manufacturing process poses several disadvantages. Significant resources are often spent creating the 3D models, which are often not used after the 2D conversions are created. The historical reason for converting 3D models to a 2D drawing format is the inability to link tolerance attributes to the three-dimensional models. Currently, the three-dimensional model are projected into convention 2D orthogonal views and dimensioned.
Additionally, both the 3D models and 2D drawings are theoretical, and do not reflect the influences of the manufacturing process, which may change the dimensions of the part or subassembly so that they differ from the theoretical, while being within the acceptable manufacturing tolerance. A number of aspects of the manufacturing process can lead to differences between the theoretical model and the as-built configuration, including product component tolerance build-up, free state versus restrained part condition, manufacturing process assembly variation, fastener-induced distortion, high interference and cold working, environmental factors such as temperature and vibration, inconsistencies in the manufacturing process, and fabrication variables such as cutter deflection.
None of these environmental factors can be evaluated when the part or subassembly is designed using the CAD software. For this reason, the 3D and 2D drawings become inaccurate representations of the parts, subassemblies, or installations, as it is actually built. If compliance with governmental or customer standards is measured against theoretical drawings, manufacturers will be unnecessarily non-compliant too often. Also, this system requires ongoing quality control, to make sure the tools, the parts, and the subassemblies comply with the specification, within the allowable engineering tolerance.
Accordingly, it is desirable to provide a system and method for manufacturing that uses as-built data in computer models and/or drawings.